Grease and process of making same



Patented Nov. 24, 1942 GREASE AND PROCESS OF MAKING SAME James AllanCamelrord, Niagara. Falls, N. E, as. signor to Alox Corporation, NewYork, N. Y., a corporation of New York so Drawing. Application November12,1940, Serial No. 365,541

7 Claims. (Cl. 252-39) This invention is concerned with. improvedlugroup of solid to semi-solid lubricants comprising mixtures of fattyacids soaps and mineral oils. The greases to which the present inventionis confined comprise metallic soaps of pre-selected petroleum acids, bywhich latter expression are here broadly meant the saturated aliphaticcarboxylic (and hydroxycarboxylic) acids of relatively high molecularweight produced by the controlled, liquid-phase, partial oxidation of amixture of mineral hydrocarbons by the process described in U. S. PatentNo. 1,768,523 to Arthur W. Burwell.

An object of the present invention is the provision of improvedlubricating greases which are readily deformed at very low temperatures(e. g., at temperatures encountered in the upper air). Another object ofinvention is the provision of lubricating greases 'which do not becomeactually solid at low temperatures. It is a specific object of inventionto provide permanently deformable barium soap greases.

I have found that lubricatinggreases possessing very desirable andsurprising properties-and in particular the very desirable property ofremaining readily deformable at very low temperatures--may be producedby dispersing in .very low cold test, substantially wax-free, minerallubricating oils metallic soaps (particularly barium soaps) ofrelatively high molecular weight petroleum acids produced, by theaforesaid Burwell process of oxidation, from substantially wax-freenormally liquid fractions of petroleum.

The invention will now be described in greater particularity and withreference to the following illustrative examples:

195 mg. KOH/gram) 250 Barium hydrate 135 Water 60 Thoroughly de-waxednaphthenic base lubricating oil, S. U. V. 130/210 F 610 Melting point offinished grease 320 F. before milling and 310 F. after milling.

Worked penetration at 77 F.--255.

The general technic of preparing the grease was as follows:

- proximately 200 parts).

The petroleum acids were heated with a portion of the hydrocarbonlubricating 'oil stock (ap- The barium hydroxide was dispersed in thewater and this dispersion was slowly added, by portions, to the abovemixture of petroleum acids and lubricating oil, at a temperature ofapproximately 200 F., with constant mechanical agitation. Heat was thenapplied gradually until all the water was driven oil, which was at atemperature of approximately 300 F. The remainder of the hydrocarbon oilwas then added slowly but continuously with agitation of the soap-oilmass. Heating was continued until the final temperature was in excess of350 F. f

The temperature selected for the heating treatment is not critical belowthe flash point of the hydrocarbon oil used as diluent: I may hold thetemperature during soap-formation at from about 140 F. to say 250 F. asdesired, and I may dehydrate at a temperature between about 300 F. andabout 400 F. or even higher. The rate of addition of the aqueousdispersion of barium hydroxide is adjusted to the readily visibleprogress of soap formation, so as to maintain the homogeneity of thesoap oil mixture. Addition of the barium hydroxide preferably iscarefully controlled to give a finished product which is not basic butrather neutral, or even slightly acid.

Should any lumpiness 'of the reaction mixture appear during progress ofthe soap-forming step, that condition may be met by temporarilysuspending additions of barium hydroxide, raising the temperature, andcontinuing the stirring until the mass is again smooth. Any rubberinessin the grease is destroyed by milling.

As will be obvious to one skilled in this art, the proportion betweenthe soap and the oil is not critical and may be adjusted to suit theparticular requirements: the larger the proportion of oil to soap, themore nearly fluid the grease. The ratio (between soap and oil) may varybetween 0.085 and 1.5 parts by weight of the soap to 1 part by weight ofthe oil. i

Example 2 l Parts by 3 weight Separated petroleum acids from theoxidation of a thoroughly de-waxed lubricating oil fraction, S. U. V.140/210 F. (saponification number mg. KOH/gram) 300 Barium hydrate 72Thoroughly dewaxed Mid-Continent lubricating oil, S. U. V. /210 F 650Water 35 Melting point of finished grease 290 F. before milling, and 285F. after milling.

Worked penetration at 77 F.2l5.

Example 3 Parts by weight Separated petroleum acids from the oxidationof a thoroughly de-waxed lubricat- Melting point of finished grease 245F. before milling, and 240 F. after milling.

Worked penetration at 77 F.-320.

' The soap-forming step of the above illustrated examples may, ifdesired, be practiced upon the crude oxidation reaction mixture(containing, besides the aforesaid petroleum acids and their esters andlactones, some unoxidized hydrocarbons and a material proportion ofneutral and unsaponifiable partially oxidized compounds includingalcoholic, ketonic and keto-alcoholic derivatives of the originalhydrocarbons): in that event, the resulting product is, of course, amixture of barium soaps contaminated by said unsaponifiables. Forobvious reasons, I prefer first to effect separation of the petroleumacids and to practice the soap-forming step upon the so-separatedpetroleum acids-rich portion of the crude oxidation reaction mixture.

The barium soap grease compositions of the invention may have meltingpoints ranging from in excess of 320 F. to as low as 160 F. I havefound, further, that these barium soap grease compositions as a grouphave, among others, the following properties: they are insoluble inwater and not readily emulsifiable with water; they are readilydeformable at very low temperatures; they have good anti-corrosiveproperties; their worked penetration values range from about 400 toabout 100 at 77 F.; they are desirably smooth and unctuous, and afterhaving been melted they reform (upon cooling), without separation, intohomogeneous compositions having the same characteristics (e. g.,appearance, lubricating ability, and physical properties generally)as'were possessed by the original greases.

I have found that the relative fluidity (or solidity) of the greasecomposition is afiected by the identity of the agent employed foraccelerating the oxidation of the initial hydrocarbonaceous material.That is to say, I have found that the soaps of petroleum acids producedby the aid of a catalytic manganese compound yield greases which aremuch more fluid than those from soaps of apparently chemically identicalpetroleum acids produced in an oxidation wherein oxidation-accelerationhad been effected by return to the oxidizer of partially oxidized,unsaponifiable, components of a previous oxidation batch. Accordingly, Imay adjust the relative fluidity of the eventual grease composition toany desired value by appropriate mingling of petroleum acids fromoxidations involving the two dissimilar oxidation-catalyzing oroxidationaccelerating materials. 7

While in the above examples the invention has been illustrated byreference to grease compositions in which the soap components are bariumsoaps, it is to be understood that the invention broadly includes greasecompositions composed of low cold test, de-waxed lubricating ofls andmetallic soaps, generally, of petroleum acids produced by theliquid-phase (Burwell process) 0111- 75 dation of normally liquid,substantially wax-free, mineral hydrocarbon mixtures. Thus, instead ofusing an oxide or hydroxide or carbonate, or other basically-reactingcompound of barium, I may use an oxide, hydroxide, carbonate or otherbasically-reacting compound of calcium, strontium, or other alkalineearth metal, or of a heavy metal such as zinc or lead, or,wherewatersolubility is of lesser importance,even of an alkali metal such assodium, potassium or lithium. The invention includes the concept ofproviding greases containing mixtures of the above mentioned soapswhereby to confer upon the greases particular properties to meetspecific requirements.

This application contains subject matter in common with that of mycopending application Serial No. 194,208, filed March 5, 1938.

I claim:

1. As a new product, a lubricating grease composition consistingessentially of a permanently readily deformable stable, homogeneousdispersion of an anhydrous, neutral to slightly acid, metallic soap ofpetroleum acids derived by oxidation of a substantially wax-free andnormally liquid mineral hydrocarbons mixture in a substantially wax-freemineral lubricating oil, which grease composition, after having beenmelted, reforms upon cooling into the same homogeneous composition.

2. As a new product, a lubricating grease composition consistingessentially of a permanently readily deformable stable, homogeneousdispersion of an anhydrous, neutral to slightly acid, alkaline earthmetal soap of petroleum acids derived by oxidation of a substantiallywax-free and normally liquid mineral hydrocarbons mixture in asubstantially wax-free mineral lubrieating oil, which greasecomposition, after having been melted, reforms upon cooling into thesame homogeneous composition.

3. As a new product, a lubricating grease composition consistingessentially of a permanently readily deformable, stable, homogeneousdispersion of an anhydrous, neutral to slightly acid, barium soap ofpetroleum acids derived by oxidation of a substantially wax-free andnormally liquid mineral hydrocarbons mixture in a substantially wax-freemineral lubricating oil, which grease composition, after having beenmelted, reforms upon cooling into the same homogeneous composition.

4. Process of forming a lubricating grease composition which is readilydeformable at low temperature, which comprises treating a mixture ofpetroleum acids derived by oxidation of a substantially wax-free andnormally liquid mineral hydrocarbons mixture with a basically-reactinginorganic compound of a metal in such proportions as to yield a soapproduct which is neutral to slightly acid, removing water from theresulting metallic soap mixture and extending the substantiallyanhydrous metallic soap mixture by admixture therewith of asubstantially wax-free mineral lubricating oil to the production of ahomogeneous grease.

5. Process of forming a lubricating grease composition which is readilydeformable at low temperature, which comprises treating a mixture ofpetroleum acids derived by oxidation of a substantially wax-free andnormally liquid mineral hydrocarbons mixture with a basically-reactinginorganic compound of an alkaline earth metal in such proportions as toyield asoap product which is neutral to slightly acid, dehydrating thetions as to yield a barium soap product which 1 is neutral to slightlyacid, removing water from the resulting barium soap mixture, andextending the resulting anhydrous barium soap mixture by admixturetherewith of a substantially waxfree mineral lubricating oil to theproduction of a homogeneous grease.

7. In a process of claim 4, the step which consists in dissolving saidpetroleum acids in substantially wax-free mineral lubricating oil beforetreating said petroleum acids with said basically-reacting metalliccompound.

JAMES ALLAN CAMELFORD.

